The present valve pertains particularly to use in dairy equipment for example which is required to be cleaned-in-place at frequent intervals in order to comply with the sanitary laws of the various states. Various fluids are passed through such equipment such as milk or orange juice and also various cleaning fluids such as cleaning solutions, acids, rinses, and so forth must also be pumped through the system and then flushed therefrom after periodical use. Consequently, in equipment of this type, the various parts must be completely disassembled so that they can be thoroughly cleaned, rinsed, or sanitized.
General examples of equipment in which the present invention is utilized are shown in various of my U.S. Pat. Nos., such as 3,352,248 issued Nov. 14, 1967 entitled "Fluid Conveying Apparatus;" 3,424,098 issued Jan. 28, 1969 and entitled "Dump Valve for Fluid Conveying Apparatus;" or 3,531,297 issued Sept. 29, 1970 entitled "Vacuum Operated timing device for Fluid Conveying Apparatus."
The present invention is an improvement over that check valve shown in my U.S. Pat. No. 3,921,652 which issued Nov. 25, 1975 and entitled "Apparatus for Automatically Mixing a Cleaning Solution," which patent has been assigned to an assignee common with the present invention. In that patent however, the shiftable valve element did not always seat properly and could otherwise malfunction by being stuck in its guide. Furthermore, that valve element required numerous parts to manufacture and stock and was otherwise more difficult to separate or take apart for cleaning. In addition, certain concentricity problems between the parts was encountered in its manufacture and use.